Process of treating hides.



UNITED STATES FATENT OFFICE.

PROCESS OF TREATING HIDES.

Specification of Letters Patent.

Patented Aug. 29, 1905.

Application filed March 31, 1905. Serial No. 253,139.

To all whom, it 11107 concern.-

Be it known that I, FRANoIs J. OAKES, a citizen of the United States,and a resident of the borough of Manhattan, city, county, and State ofNew York, have in vented certain new and useful Improvements inProcesses of Treating Hides, of which the following is a specification.

My present invention relates more particularly to the preparation ofskins designed to produce such final leather products as are designatedas glazed. In such skins it is essential that the grain of the surfaceshall be as low and smooth as possible in order to insure the desiredfinish and appearance and also that the fibers shall be left in an opencondition in order to secure the best results from the mineral tannageto which they areusually subjected.

The object of my invention is to produce a process more economical andcertain than those previously practiced and which with less injury toand consumption of the hide substance generally than heretofore willnevertheless insure the desired surface, at the same time removecementing material, so as to leave the fibers in the required opencondition, and also assist by removal of undesired lime or calciumcompounds.

I attain these objects by my novel process, which is addressed to thehides after application thereto of the well-known dehairing ordepilating processes, which leave in the skins an undesired percentageof caustic lime.

My said process consists, generally speaking, in subjecting the hides orskins after dehairing, as aforesaid, to the action of an aqueous bathcontaining sulfur and an albuminoid, thus dispensing with theeXcremental ingredients heretofore relied on for the purposes mentioned.By albuminoids in this connection 1 mean to refer to those organicbodies as a class which are characterized as contaming nitrogen andphosphorus, being bodies more or less indiscriminately designated asalbuminous substances or proteids or nitrogenous matter, examples ofwhich are, for instance, casein, blood albumin, animal tissue, fish, &c.

My said process is preferably practiced as follows, for instance, viz:Into a volume of water sufficient to insure convenient handling of thehidessay in the proportion of about three pounds of water to one poundof the moist hides l preliminarily introduce sulfur and an albuminoid,preferably casein, in the proportion of, say, about five per centum ofeach, computed on the weight of said hides. The bath thus prepared isallowed to stand at a temperature of about 100 Fahrenheit sufiicient-lylong-say several days or until decomposition and consequent putrefactionis established ofthe casein-and this may be hastened, if desired, byintroducing a small quantity of already decaying albuminous matter-as,for instance, putrid cheese. When the said putrefaction is observed tobe well under way, the hides or skins as they come from the saiddehairing process are introduced into the bath. the temperature of whichis maintained at 100 -Fahrenheit during the period of immersion.

The hides are leftto soak in the bath until the required surface ofgrain has been attained, when their fibers will also be found to be inthe desired open condition and substantially relieved of the undesiredcalcium compounds.

It will be understood that my said bath once instituted may bethereafter continuously utilized upon successive charges of hides, itbeing only necessary to maintain therein substantially the aforesaidrequired proportions of sulfur and albuminoid by adding fresh charges ofthose agents as they become exhausted. I have found, for instance, thatwith each charge of hides an addition of one per cent. of sulfur and twoper cent. of casein computed on the weight of the hides is sufficient tomaintain the efficiency of the bath, and after the decomposition hasbecome well established subsequent additions of putrid cheese may bedispensed with. It will also be understood that other albuminoids may besubstituted for casein with substantially the same results.

The time required for the best results from mysaid bath will obviouslyvary somewhat,

according to the particular nature and size of the hides or skinstreated, but may be said to be approximately the same as in the case ofprevious processes involving baths containing dog-dung and otherexcrementitious agents.

By my process, as described, I am enabled advantageously to dispensewith all such excrementitious agents hitherto employed to secure thedesired results.

While the reactions occurring in my bath involve also putrefactiveaction, the improved and distinctive results attained thereby seem tojustify the conclusion that the character and action of the bacteriapresent differ from those produced by and relied upon in excrementitiousprocesses, being manifestlymore benign relatively to the gelatin of thehides and more certain and uniform in their action upon the cementingmaterials of the fibers, including particularly those required to bereduced in order to present the aforesaid required low and smooth grainat the surface. In other words, injurious and undesired types ofbacteria hitherto present in excrementitious processes are avoided by myinvention. Comparative tests have demonstrated that the sulfurplays anessential and important part in securing the results attained by myprocess as aforesaid and also reduces the otherwise undesirably alkalinecharacter of the bath without hindering the required putrefaction ordecomposition.

It seems that the putrefaction described develops in the bath anundesirable ammoniacal condition, the intensity of which is reduced bythe presence of the sulfur, which tends to formation of sulfids of aweakly alkaline and comparatively benign nature for the purposes inhand, the beneficial results secured by my process being substantiallydue to the action of the sulfur upon the ammonia produced by theputrefactive decomposition of the albuminoid employed.

The hides or skins when withdrawn from my said bath will usually appearstill slightly alkaline in reaction, in which case if intended forsubsequent chromium or other mineral tannage they should be subjected toone of the usual pickling processes, the object of which is, as wellknown, to remove therefrom the last remaining traces of calciumcompounds, or if vegetable tannage is to be applied then in that casethe hides should be drenched, and thus in either case brought to therequisite acid condition.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is the following, viz:

1. The process of treating hides which consists in soaking them in abath containing, besides said hides, putrefying albuminous matter andsulfur.

2. The process of treating hides which consists in soaking them in abath containing, besides said hides, a substantial amount of aputrefying albuminous matter, say five per centum of the-weight of thehides and a substantial amount of sulfur, say likewise five per centumof the weight of the hides.

FRANCIS J. OAKES.

